In Situ Thermometry Measuring Temperature Flashes Exceeding 1,700℃ in 8 mol% Y_2O_3-Stablized Zirconia Under Constant-Voltage Heating

摘要

Using AC impedance spectroscopy as a means of in situ thermometry, temperature runaway over l,500℃ within a few seconds was observed for the first time in dense 92 mol% ZrO_2-8 mol% Y_2O_3 (8YSZ) ceramics heated under a constant voltage. Such runaway is especially pronounced when starting from a low background temperature in samples of a small surface-to-volume ratio, and is expected to be commonplace during flash sintering of porous ceramic cubes or cylinders. The method of AC impedance-based thermometry is applicable to other ceramics with a well-defined conduction mechanism at high temperature.